Apparatuses for automatically feeding flat-folded packaging blanks, for example cartons—with or without laminate—to a filling machine for raising and filling are previously known in the art. One such apparatus displays a magazine for packaging blanks and a discharge device for individual discharge of these blanks one by one out of the magazine.
The magazine usually displays a channel in which the blanks are disposed in queue or file for feeding through the magazine towards the discharge device. The channel displays a bottom which supports the blanks, side walls which laterally define the channel and guide the blanks, a front stop against which the first blank in the magazine is urged in order, in this position, to be grippable by the discharge device for discharge out of the magazine, as well as a carrier which, by applying a force from the rear against the last blank in the magazine thereby urges the first blank in the magazine against the stop.
In magazines of the above-mentioned type it is desirable to realise an even and uniform advancement of the blanks on their displacement through the magazine. This has hitherto been realised int. al. in that various measures have been implemented to minimise the friction which occurs between the bottom of the magazine and that part of the blanks resting against the bottom.
Another measure which has been proposed in the art is to provide control devices which regulate the force which, via carriers, abuts against the last blank in the magazine which, by a transfer of force via all of the other blanks in the magazine, finally urges the first blank in the magazine against the stop. This force is proposed to be greater when the magazine is full and smaller when the magazine contains a smaller quantity of blanks.
A further phenomenon to take into consideration when blanks are to be advanced through a magazine is the so-called spring back effect. This occurs when flat-folded, folded over/flattened blanks show a tendency to spring back to a state of equilibrium which, for example, may contribute to an advancement force which defies ready control.